CUYAHOGA FALLS, Ohio—At the recent Battle at Stonehedge pinball tournament here, Jessie Carduner cursed her ninth-place finish and vowed to get professional help.

"I'm thinking about getting a hypnotist," said the 51-year-old linguistics professor at Kent State University. Ms. Carduner, who is 4 feet 10 inches tall and wears high heels so she can get a better view of the game, says she practices up to 30 hours a week but...